Dhaka, Aug. 14 -- Nine-time Grand Slam champion Monica Seles has revealed she was diagnosed with myasthenia gravis - a neuromuscular autoimmune disease - three years ago.

The 51-year-old has chosen to go public with the rare long-term condition, which causes muscle weakness, to raise awareness before this month's US Open. Seles first noticed symptoms of the condition, which can affect most parts of the body - including the muscles that control the eyes, around five years ago.

"I would be playing [tennis] with some kids or family members, and I would miss a ball," former world number one Seles told The Associated Press. "I was like, 'Yeah, I see two balls.' These are obviously symptoms that you can't ignore.

"It took me quite some time ...